Who is Demi Lovato’s shade-filled tweet about?

The shade is real!

Lovatics went wild on Thursday night when Demi Lovato took to Twitter with a simple, seemingly shade-filled message.

The “Sorry Not Sorry” singer, 25, wrote, “Good luck on your blog,” which prompted her millions of fans to quickly start speculating.

Lovato, who has not shied away from a good feud in the past, did not clarify who she was talking about, but fans quickly pointed to Mike Bayer – a CAST Centers life coach who appeared with Lovato during an emotional interview on Dr. Phil earlier this year and who has also gone on tour with the pop star.

Bayer has previously been credited with helping Lovato get sober in the past after her 2011 rehab stint.

On Thursday, Bayer posted a video that many fans thought was specifically aimed at Lovato, prompting her tweet.

“I worked in entertainment for many years being a life coach for a lot of different pop stars and actors, and my biggest pet peeve is when they use excuses because they call themselves artists,” Bayer says in the clip, throwing up air quotes around the word “artists.” “I’m here today to explain to you that being an artist and being talented are two different things. To me being an artist is living your authentic life.”

Bayer went on to say, “I think if somebody uses it as an excuse to be late, or insincere, or rude, or unapologetic, that’s not being an artist, that’s being a jerk. And you shouldn’t stand for that.”

Fans quickly started commenting, “Good luck with your blog,” on the post, calling Bayer out for being “negative.”

Lovato is a co-owner for the CAST Centers and included messages from the center in her recent world tour. While on the tour, the singer released an emotional new song called “Sober.” In it, she seemingly confesses to no longer being sober after years of working on her sobriety.

“Demi relapsed and started drinking alcohol again,” a source previously told ET. “Her song is intense, but that’s how she deals. She has to be brutally honest and put it out there so that she’s not burdened with holding on to her struggles privately.”

Lovato’s tour wrapped shortly after the song was released, and she has not clarified to her fans whether or not she’s seeking treatment for the relapse or whether she is currently sober.

“We met after a bad mushroom trip,” Bayer told ET at the time. “She asked for help and her therapist and another person had both said to call Mike Bayer. That was the beginning of our journey, from her history, struggling with addictions, cutting, eating disorder, and then now, getting to the other side of it where it’s about empowerment, advocacy, how to change the world.”

He added that, “Demi has done a complete 180. She’s the biggest pop star on the planet who talks about her issues in a public way. That is a miracle in the entertainment bus.”

Following the two posts, Lovato and Bayer have both unfollowed each other on Twitter.